The "00:00:00" in "Default is 00:00:00." will be in bold style.

Don't show the reStructuredText markup ":option:`foo`" in help content.

Using bulleted lists can avoid unintended syntax highlighting.
For "--fs-safe-rules", we will put a part of content into inline code
  blocks later.

For new users of CLI.

There are some lines starting with two or more spaces contain the
  options should be links. To achieve it, the following types of lines
  should not be processed:
  - Starting with two or more spaces followed by a "%(prog)s";
  - Starting with two or more spaces followed by a full-length option;
  - Starting with an "Example: ".

This will make the documentation more clear and informative both on the
  rendered webpages and in the manpage as well as the "--help" content.
- On webpages, we will get inline code blocks;
- In the manpage, we will get emphasized words (bold);
- In the help content, we will get words enclosed in single backticks.
This will help us remove reStructuredText markups from the docs.
About "\$A":
  "\\$A" has been put into a code block, so the single backslash will be
  displayed correctly in the help content. For rendered docs, escaping
  backslashes is now no longer required since we did it automatically.
---
A useless non-capturing group has been removed as per the suggestion:
  #4659 (review)
  Thus,
Co-authored-by: bastimeyer <mail@bastimeyer.de>

This will make the documentation more clear and informative both on the
  rendered webpages and in the manpage as well as the "--help" content.
- On webpages, we will get inline code blocks;
- In the manpage, we will get emphasized words (bold);
- In the help content, we will get words enclosed in single backticks.
This will help us remove reStructuredText markups from the docs.
About "\$A":
  "\\$A" has been put into a code block, so the single backslash will be
  displayed correctly in the help content. For rendered docs, escaping
  backslashes is now no longer required since we did it automatically.
---
A useless non-capturing group has been removed as per the suggestion:
  streamlink#4659 (review)
  Thus,
Co-Authored-By: bastimeyer <mail@bastimeyer.de>